(1) Field of the Invention
The present invention generally relates to improving performance of combustion engines. In particular, the present invention is directed to a system and method for controlling turbulence in a combustion engine.
(2) Description of the Related Art
Manufacturers are continually trying to improve engine performance and fuel economy while also reducing undesirable emissions. To achieve this, internal combustion engines are being designed to improve the mixing of intake air and injected fuel in the combustion chamber and to direct the flow of air and air-fuel mixture in order to provide an optimum mixture. The use of tumble and/or swirl flows of air in the combustion chamber have been used in an effort to achieve an optimum air-fuel mixture.
Various control valves have been used within internal combustion engines in order to introduce swirl flows of air and fuel into the engine's cylinders. The control valves are used to alter the flow of air into the cylinder during certain vehicle operating modes (e.g., during relatively low engine speed and load conditions), and are generally effective to create turbulence within the cylinder, thereby improving combustion within the cylinder.
In order to be more efficient at low revolutions per minute (rpms), swirl can be introduced to have a better mixing of the air and fuel in the runner before the intake valve. Swirl inducing valves are typically designed to substantially block an air intake runner at low rpm, which increases air velocity, thereby introducing swirl as it flows through the opening in the valve. This flow of air into the cylinder creates a swirling effect or turbulence, which causes the fuel rich mixture and fuel lean mixture to combine and provide improved combustion. At high rpms when the air velocity is fast, the valve opens.
While open, the valve can restrict some of the airflow since it can be an obstruction in the runner. This result is not desirable. Air pulsations applied to the valve can cause noise and vibration. The valve can be subject to high stress and heat during specific events such as backfire. Installation of swirl-inducing valves is often expensive and requires machining processes.